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Results for “Microbiological Phenomena”

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At least 19 recordsLinked to original sources
PubMed1966

Response of the extract-release volume and water-holding capacity phenomena to microbiologically spoiled beef and aged beef.

The aging of ground beef was effected by storing in gas-impermeable, sterile plastic bags with incubation at 7 and 15 C. Control meat from the same preparations was wrapped in aluminum foil and stored at the same temperature. In three experiments where control meat was tested, aged meat did not attain a log bacterial number of ca. 8.4 per gram until an average of 6 days after this level was reached in control meats. This degree of difference was shown in values for both extract-release volume (ERV) and water-holding capacity. The previously reported ERV value of around 25, which was found to correspond to an average log bacterial number of ca. 8.5 per gram for ground beef allowed to spoil in aluminum foil and freezer paper, was approximated for aged meats, which required an average of 9.7 days to attain this number compared with 4.1 days for unaged meats. Plate count methods indicated the predominant flora of aged beef to be gram-negative, facultatively psychrophilic rods.

Bacteria↗
PubMed2003

Models and microbiology: Pasteur and the body.

Louis Pasteur developed a model of the body as a culture vessel in the late 1870s as an explanation of both natural and acquired immunity, and other investigators quickly applied the model in the explanation of other microbiological phenomena, principally the tissue tropism seen in the normal and the pathological flora. This paper will argue that although Pasteur quickly abandoned the model, it persisted as an explanation of tissue tropism for nearly 70 years, structuring the interpretation of data by and guiding the research of a diverse group of microbiological researchers.

Equipment and Supplies↗
PubMed2004

Single-cell microbiology: tools, technologies, and applications.

The field of microbiology has traditionally been concerned with and focused on studies at the population level. Information on how cells respond to their environment, interact with each other, or undergo complex processes such as cellular differentiation or gene expression has been obtained mostly by inference from population-level data. Individual microorganisms, even those in supposedly "clonal" populations, may differ widely from each other in terms of their genetic composition, physiology, biochemistry, or behavior. This genetic and phenotypic heterogeneity has important practical consequences for a number of human interests, including antibiotic or biocide resistance, the productivity and stability of industrial fermentations, the efficacy of food preservatives, and the potential of pathogens to cause disease. New appreciation of the importance of cellular heterogeneity, coupled with recent advances in technology, has driven the development of new tools and techniques for the study of individual microbial cells. Because observations made at the single-cell level are not subject to the "averaging" effects characteristic of bulk-phase, population-level methods, they offer the unique capacity to observe discrete microbiological phenomena unavailable using traditional approaches. As a result, scientists have been able to characterize microorganisms, their activities, and their interactions at unprecedented levels of detail.

Animals↗
PubMedDate not supplied

[Biologic tolerance of prolene prosthesis in inguinal hernia repair].

The aim of this study was to evaluate the efficacy, safety and durability of a calibrated inguinal hernioplasty polypropylene prosthesis, particularly in relation to the microbiological phenomena that may set in the vicinity of the polypropylene plugs and mesh employed. Over the period from January 1994 to December 2002, 1416 operations were carried out for inguinal hernia. In 5 of these patients we conducted an immunological study to assess serum cytokine concentrations. In addition, we incubated peripheral blood mononuclear cells for 24 or 72 hours in RPMI 1640 medium added with 10% FCS, with or without 0.5 cm2 of polypropylene. We then evaluated cytokine levels in the supernatant of these cultures. It proved impossible, either in vivo or in vitro, to detect appreciable levels of IL-10 or IP-10. Serum levels of IFN-gamma, TNF-alpha, IL-18 and IL-6 increased in the postoperative phases as compared to the preoperative period. In the study performed in vitro, in the presence of prosthetic material there was a remarkable increase in the production of TNF-alpha and INF-gamma both in basal conditions and after an appropriate mitogenic stimulus. The results of this study allow us to speculate that the use of polypropylene induces remarkable chemotactic activity in the tissues adjacent to the prosthesis. The in-vitro study data suggest that the presence of polypropylene may stimulate the immunocompetent cells of patients with prosthetic implants.

Adolescent↗
PubMedDate not supplied

Microbial differences in 2 clinically distinct types of failures of osseointegrated implants.

The microflora associated with osseointegrated implants suspected of failing from infection or trauma were evaluated. Of 75 patients examined, 11 demonstrated failing fixtures. 22 of 48 fixtures failed in 6 fully edentulous patients and 10 of 34 failed in 5 partially edentulous patients. The etiology of failure was attributed to infection if there was bleeding, suppuration, pain, high plaque and gingival indices and granulomatous tissue upon surgical removal. Traumatic etiology was suspected in the absence of these signs. Direct phase-contrast microscopy and culture analysis were performed on samples from the implant sulcus, the implant itself and the extraction socket. The 2 failure types exhibited distinct bacteriologic profiles. For implants failing with infection, spirochetes and motile rods averaged 42% of total morphotypes. Many suspected periodontopathic organisms including Peptostreptococcus micros, Fusobacterium species, enteric gram-negative rods and yeasts, constituted high proportions of the cultivable microflora. In contrast, implants failing from suspected traumatic etiology demonstrated a morphotype profile consistent with periodontal health and cultivable microflora predominated by streptococci. When evaluating the time of failure after initial insertion, it was found that fixture loss resulting from infection occurred most often between initial placement and second-stage surgery, whereas failure in the absence of infection occurred primarily after insertion of the final prosthesis. The terms infectious and traumatic failure have been introduced to describe these 2 clinically and microbiologically distinct phenomena.

Alveolar Process↗